Adaptive beam-space nulling of multipath signals

A beam-space nulling algorithm is described which has potential for applications in communication circuits which are degraded by multipath signals. Results are presented from tests of the algorithm using real multipath data. The data used in these tests were recorded using a beacon and a large aperture antenna. These measurements were carried out on an over-water path. The direct signal, i.e. the signal that propagated via the shortest path from the beacon to the antenna, is selected as the desired signal and the indirect signal(s), i.e. the signals that propagated via reflection from the surface of the water, as the unwanted signal(s). In many cases the wanted and unwanted signals are separated by less than a beamwidth. Two examples are given.<>